Phenolic constituent, antioxidative and tyrosinase inhibitory activity of Ornithogalum narbonense L. from Turkey: A phytochemical study

This study examined the antioxidant and anti-tyrosinase activity and phenolic profiles of three extracts (ethyl acetate, methanol and water) obtained from different anatomical parts (bulb, stem and seed) of Omithogalum narbonense. Antioxidant activity of the extracts was evaluated using DPPH*, ABTS(+)*, FRAP, CUPRAC, metal chelating and phosphomolybdenum assays. Tyrosinase inhibitory activity was measured using the modified dopachrome method with L-DOPA as the substrate. Phenolic content of the extracts varied according to plant part and extraction solvent and included HPLC DAD, epicatechin, rutin, ferulic, protocateuchic p-hydroxybenzoic, chlorogenic, caffeic, benzoic and rosmarinic acids. The ethyl acetate extract of O. narbonense bulb samples demonstrated the most antioxidant and anti-tyrosinase activity and had the highest phenolic content. All other extracts showed moderate antioxidant and anti-tyrosinase activity. O. narbonense extracts, especially ethanol extract of O. narbonense bulbs, may have dietary and medicinal applications. (C) 2015 Elsevier B.V. All rights reserved.